Checking root filesystem on ArchLinux

My shiny new ArchLinux on the Pogoplug was complaining about root filesystem not being clean. I tried usual approach of placing /forcefsck file in the root folder and rebooting. Although the file was removed at the next boot the filesystem check still complained.

I went to the IRC to the #arch-linux-arm channel which is recommended on the website, but no one appears to know how to do this on the running system. The only recommendation that I got, was to take out the drive and put it in to another Linux box. Well, this being a USB flash drive makes it possible to do so. But imagine an internal disk and this quickly becomes less than practical solution.

So I went to the "Internets" and did a search. As expected someone already asked this question and got a multitude of answers which helped me to put together a procedure. So here it goes:

• Execute following command:
  fuser -v -m /
  This will give you a list of all processes having files open on the filesystem. Look for the processes that have F or f flags set. For example:
  root        182 .rce. dhcpcd
  root        197 frce. crond
  root        219 .rce. sshd
  ntp         226 Frce. ntpd
  So it looks like the crond and the ntpd have files open.
• Shutdown these processes by using following command:
  rc.d stop ntpd
  Shutdown all of the processes that have files open on the filesystem.
• Now you can remount filesystem using following command:
  mount -r -o remount  / 
  
  If you correctly shutdown all of the processes remount should complete without any error.
• At this point you should be able to do a filesystem check:
  e2fsck /dev/sda1 or e2fsck -y /dev/sda1 

I hope that you found this post helpful and it saved you some time.